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My QCX (#241) suffered from the power on issue. After power on it did not start. I had to switch power off and then on again. My first idea was that the display was not reset properly but it turned out that the processor itself did not start.
After a closer look at the schematic I suspected L6 as the problem. I reduced it from 100?H to 47?H and now I do not have problems anymore:-)
I think that supply voltage at VCC did not rise fast enought which caused the reset circuit to stuck.
Regards
Karsten - DL3HRT
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Dear all,
I got a power issue, and it is from not L6 but L5.
My problem is "A row of blocks appears on the top row", described at manual 6.3. With measurement, LCD's D4-D7 is about 1V. I understood CPU didn't work with LCD. I re-soldered LCD, pin header and atmega328p, but not solved.
Also I read 328p fuse bit with ArduinoISP, so I could read it (and it shows external xtal).
Next, I tested the pins of 328, VCC is 5V but AVCC is only 4V. I checked a resistance between AVCC and 5V, it is 600ohm. So, I re-soldered L6, work fine.
It caused by my bad soldering of course, also I suspect the wires of inductors is coated something.
Now it works well for receiving without C1 is completely open. ?(Best freq is 6750kHz, No problem to use in 40m.)
Regards.
toyo / JG2RZF?
My QCX (#241) suffered from the power on issue. After power on it did not start. I had to switch power off and then on again. My first idea was that the display was not reset properly but it turned out that the processor itself did not start.
After a closer look at the schematic I suspected L6 as the problem. I reduced it from 100?H to 47?H and now I do not have problems anymore:-)
I think that supply voltage at VCC did not rise fast enought which caused the reset circuit to stuck.
Regards
Karsten - DL3HRT
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Toyo
nice work!? I had similar problem - melting insulation from wire used for inductors.?
patiently do the receiver calibration -- please note the re-scaling of the indicator as the receiver gets better.?
perhaps other JA builders of the QCX should check in now -- as you could converse with them on alignment of the rig.? the QCX receiver is wonderful.?
not sure what you mean about best frequency being 6750 kHz -- but please note that exact peaking of C1 may be less important on 40m.? enjoy your rig progress.
73 Curt
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Curt,
As you say, I also think C1 tuning is not so important,
because the sensitivity of my QCX is better than my TS-690 for my ear.
Thank you for your reply!
toyo / JG2RZF.
Toyo
nice work!? I had similar problem - melting insulation from wire used for inductors.?
patiently do the receiver calibration -- please note the re-scaling of the indicator as the receiver gets better.?
perhaps other JA builders of the QCX should check in now -- as you could converse with them on alignment of the rig.? the QCX receiver is wonderful.?
not sure what you mean about best frequency being 6750 kHz -- but please note that exact peaking of C1 may be less important on 40m.? enjoy your rig progress.
73 Curt
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I have this problem with my QCX. I will try this fix too.? I wonder if Hans will comment?
Nigel M0NDE
On 9 Oct 2017 12:49, "DL3HRT" < dl3hrt@...> wrote: My QCX (#241) suffered from the power on issue. After power on it did not start. I had to switch power off and then on again. My first idea was that the display was not reset properly but it turned out that the processor itself did not start.
After a closer look at the schematic I suspected L6 as the problem. I reduced it from 100?H to 47?H and now I do not have problems anymore:-)
I think that supply voltage at VCC did not rise fast enought which caused the reset circuit to stuck.
Regards
Karsten - DL3HRT
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I had wondered whether the extra delay in voltage getting to the VCC pin due to C47 being 470uf in some kits (as opposed to 220uf per the schematic) was causing initialisation issues for the controller in those kits with the 470uf cap. And when the second switch on happens there is still some charge left in C47 so VCC gets to voltage quicker and the initialisation of the chip occurs properly.
I had the switch on issue and I had the 470uf cap. But I changed it to 220uf and still have the same issue. So there went that idea.
I've reflowed the solder on L5 and L6- no change. Will try 47uH for L5 and or L6 when I get some.
73
Simon VK3ELH
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Hello,
Do you still have Firmware Version 1.0? You should change to V. 1.0b and your problem is solved. 73 de
Hajo dl1sdz
---
Cela est bien dit, mais il faut cultiver notre jardin.
???
I had wondered whether the extra delay in voltage getting to the VCC pin due to C47 being 470uf in some kits (as opposed to 220uf per the schematic) was causing initialisation issues for the controller in those kits with the 470uf cap. And when the second switch on happens there is still some charge left in C47 so VCC gets to voltage quicker and the initialisation of the chip occurs properly.
I had the switch on issue and I had the 470uf cap. But I changed it to 220uf and still have the same issue. So there went that idea.
I've reflowed the solder on L5 and L6- no change. Will try 47uH for L5 and or L6 when I get some.
73
Simon VK3ELH
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Dear Hajo,
I am running the latest firmware, I still have the switch on issue here.
73 Nigel M0NDE
On 11 October 2017 at 10:43, Hajo Dezelski <dl1sdz@...> wrote: Hello,
Do you still have Firmware Version 1.0? You should change to V. 1.0b and your problem is solved. 73 de
Hajo dl1sdz
---
Cela est bien dit, mais il faut cultiver notre jardin.
???
-- 73 de Nigel Evans M0NDE QTH Burnham on Sea, Somerset GEO Shop shop@...------------------------------------------------------------------------------
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Hajo,
Yes I am running 1.00b also (and have switch on issue).
73
Simon VK3ELH
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I am running 1.00b also (and have switch on issue).
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As Karsten says:
You can reduce the 100uH inductor to 47uH to solve the power-on issue. It does not affect everyone anyway. I have never seen it on any of my dev/prototype/pre-production/production kit builds, with three different power supplies.?
I am currently preparing 1000 more QCX kits, for serial numbers 1500-2500 (approx), and I have replaced the 100uH inductors with 47uH.?
If you don't have a 47uH inductor you could also just try shorting out the inductor. The purpose of the inductor was to separate the supplies to the digital parts of the circuit and the analogue, to keep digital noise out of the receiver. However you may find that there is no noise even when you short out the inductor. So you could give that a try too.?
73 Hans G0UPL
On Thu, Oct 12, 2017 at 7:47 AM, John PD7MAA <pd7maa@...> wrote:
I am running 1.00b also (and have switch on issue).
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Hallo Hans,
I do not have any experience with AVRs. I read in the datasheet that you can set the fuse bits for a time-out-dalay after reset of about 65 ms. This should be enough for the the 100 microH and the 220 microF. Or not? Or are there big power supply current jumps during the beginning of the code?
73 de Mike, DJ9BX
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PA0EJH gave me a tip.
The 100uH inductors in the kit are verry small thus having some resistance By simply mounting larger types with lower resistance the problem was solved on my QCX.
73 John PD7MAA
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Had same issue, low power to ATMega\LCD (poor contrast adjustment, random microprocessor resets).
Cause turned out to be residue on the leads of L6, despite the solder joint looking good it exhibited resistance.
This case fits with Hans findings of no issues with 100uH, at a guess
the residue is a by-product of the manufacturing process and therefore variable.
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On 17/10/17 17:47, John PD7MAA wrote: PA0EJH gave me a tip.
The 100uH inductors in the kit are verry small thus having some resistance By simply mounting larger types with lower resistance the problem was solved on my QCX.
73 John PD7MAA
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Hans G0UPL wrote... Reducing that 100uH inductor to 47uH seems to do
the trick... so the next kits manufactured will
have this change. I have #625 on the way, and #928 in the queue. I'm assuming #625 won't have the 47uH inductors already. Would you recommend that I pre-emptively order up a handful of them, or should just wait and see if I experience a start-up problem? -- 73 Keith VE7GDH
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Hi Keith
It it was me I'd just wait and see... the problem doesn't seem to affect everyone anyway. The inductor value is not critical. It is for keeping noise from the digital part of the circuit out of the supply, where it could leak back into the analogue parts of the circuit. Just a noise filter.?
73 Hans G0UPL
On Wed, Oct 25, 2017 at 9:08 PM, Keith VE7GDH <ve7gdh@...> wrote: Hans G0UPL wrote...
> Reducing that 100uH inductor to 47uH seems to do
> the trick... so the next kits manufactured will
> have this change.
I have #625 on the way, and #928 in the queue. I'm
assuming #625 won't have the 47uH inductors already.
Would you recommend that I pre-emptively order up a
handful of them, or should just wait and see if I
experience a start-up problem?
--
73 Keith VE7GDH
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Hi all,
I've changed both inductors to 47uH and this issue was actually worse as it occured every time at first power with second power up only working if done within about 2 seconds.
And then things got worse. Now Ive got just the top row of squares and it wont start properly at all. Nothing was changed in between starting properly on the second power up and now where it looks the micontroller is not working at all. No band noise at all. The Clk test pins are producing nothing. The voltages on the lcd pins are not right. There is a quiet hiss with the audio at full volume. I think the chip is dead.
73
Simon VK3ELH
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Hi Simon
I am building the 20M version. I had a issue with no display at power on, but it did come on at the second try. For your info my brightness pot is turned fully anticlockwise.
I changed L6 to 47uH and it was the same problem with no display. However I removed C47 470uF (I was going to reduce it) and it works every time now.
May help?
73
Mike
G0CVZ
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Thanks Mike. C47 was one my suspects earlier so I replaced it with 220uf (my kit had 470uf). The lower value made no detectable difference. I pulled the chip and put it in an arduino uno and the IDE recognised the chip so may its not completely dead. I'll try to reflash it when I get a chance and see if that wakes it up. And then see if no C47 works. I see there is still some filtering at C37 on the 5v line.
Thanks for the idea.
73
Simon VK3ELH
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Toyonori FUJIURA
Nigel Evans M0NDE
Hajo Dezelski
John PD7MAA